This invention relates generally to the machining of workpieces and relates, more particularly, to computer-controlled machining operations wherein a cutting tool is moved relative to a workpiece along a predetermined, or preprogrammed, path to effect a cut in a workpiece held by the holder.
When a computer program is prepared for controlling the path of relative movement between the cutting tool and workpiece holder in a computer-controlled machining apparatus, the size and shape of the cutting edge of the tool is normally presumed not to experience changes during a machining operation or possess dimensional errors. Thus, the relative movement between the cutting tool and workpiece holder controlled by the program commonly does not compensate for wear-related changes in the cutting tool edge, such as may occur during a machining operation, or for imperfections in the cutting tool edge, such as may exist in a new cutting tool. In machining applications in which a relatively high degree of precision is required, the inability of such machining apparatus to compensate for changes and/or imperfections in the size and shape of a cutting tool edge may result in erroneous cutting of the workpiece and ultimately, in an unacceptable product.
It would be desirable to provide a computer-controlled machining apparatus wherein adjustments may be made to the preprogrammed path of relative movement between the cutting tool and workpiece holder for taking into account variations between the actual size and shape of the cutting edge during a machining operation and the assumed size and shape of the cutting edge upon which the preprogrammed path is based so that the dimensional accuracy of a product formed with the apparatus is enhanced.
Accordingly, an object of the present invention is to provide a system and method for a computer-controlled machining apparatus for generating information based upon the actual size and shape of the cutting tool edge at a preselected stage of a machining operation so that the preprogrammed path of movement between the cutting tool and the workpiece holder may be adjusted to take into account the actual size and shape of the cutting tool edge.
Another object of the present invention is to provide such a system and method wherein the information generated relating to the actual size and shape of the cutting tool edge utilizes an image of the tool edge.
Still another object of the present invention is to provide such a system wherein the components of the system utilized for generating information relating to the actual size and shape of the cutting tool edge is not required to contact the cutting tool during an information-gathering operation.